Vasectomy is the procedure of dividing the vas (the tube that delivers the sperm from the testis to the prostate) in order to prevent conception. It is the most common method of male contraception in this country where about 500,000 vasectomies are done each year. It is an elective surgical procedure to achieve sterility. Since vasectomy simply interrupts the delivery of the sperm, it does not change the hormonal function of the testis and sexual drive and ability remain intact. Since most of the semen is composed of fluid from the prostate, the semen will look the same. Although the man continues to have sexual intercourse and climax as before, his semen does not contain sperm and he cannot father a child following a vasectomy.